S, 5620 terminals, layers

[Ross Porter]

Has anyone successfully used S's tty5620 function/terminal driver?

We have been successfully using S in a tek4014 layer, but have been
underwhelmed by the graphics performance (relative to that of a
dedicated graphics terminal (we have hp2623s)).  We would like
to avoid the emulation overhead of tek4014 by running S in a generic
layers window.  [old] S has tty5620 expressly for this purpose.
However:

  > tty5620
  sorry, pid 1521 was killed: exec: error reading data area
  Error: Device not active
  Error in newdv

Any ideas?  Does it sound like a problem with downloading (to layers)
the S-specific driver, or a problem with loading the actual driver?

Our config:

  DEC Microvax II, Ultrix 2.2
  old S w/src
  new S (not currently used)
  S plus (perhaps in the near future)
  1MB 5620 (3 of 'em)

If you don't happen to know the answer, do you perhaps know of a
support company who might 'sell' us the answer?  As far as I know,
we can't call AT&T despite the $800 we paid for New S.

Any help is appreciated, 

Ross
ross at cattell.psych.upenn.edu